Communication apparatus capable of adjusting volume of voice to be reproduced

ABSTRACT

A communication apparatus through which voice communication can be performed, including: a line interface portion which receives and transmits data form and to a line and which includes a data access arrangement device in which is incorporated a detection circuit that detects at least one of a line voltage and a line current; a voice reproducing device which reproduces a voice that is based on voice communication data transmitted from the line to the line interface portion; and a volume adjuster which adjusts reproduction volume with which the voice is to be reproduced by the voice reproducing device, on the basis of a detected value of the detection circuit.

The present application is based on Japanese Patent Application No.2004-105128 filed on Mar. 31, 2004, the contents of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates in general to a communication apparatusincluding a line interface portion which receives and transmits datafrom and to a line and which includes a data access arrangement devicein which is incorporated a detection circuit capable of detecting atleast one of a line voltage and a line current.

2. Discussion of Related Art

As a communication apparatus, there is conventionally known a telephoneset which reproduces, by a telephone receiver thereof, a voice signaltransmitted from public switched telephone network (PSTN) via atelephone line. This kind of telephone set suffers from, due totransmission loss, variation in an input level of the voice signalinputted into the telephone receiver depending upon the length of thetelephone line connected to an exchanger. Therefore, in the telephoneset connected to the telephone line which is relatively long, thereproduction volume of the voice to be reproduced by the telephonereceiver is small, so that a user may feel difficulty in hearing thevoice during conversation with a communication partner.

To solve the problem indicated above, there is conventionally proposed atechnique as disclosed in JP-A-5-347661, for instance. In the disclosedtechnique, a detection circuit capable of detecting a line current isdisposed at a position that is nearer to a line than a line interfaceportion which transmits a dial signal and which performs controlrelating to status of closing and connection of the line, and anamplification factor of an amplifier provided on a telephone receiver isadjusted on the basis of a detected value of the detection circuit.

SUMMARY OF THE INVENTION

In the conventional technique described above, however, the detectioncircuit is provided exclusively for adjusting the amplification factorof the amplifier of the telephone receiver, undesirably pushing up thecost of manufacture of the telephone set.

The present invention has been made in the light of the situations asdescribed above. It is therefore an object of the invention to provide acommunication apparatus capable of adjusting the reproduction volume ofa telephone receiver without providing a detection circuit exclusivelyfor adjusting the reproduction volume and independently of a lineinterface portion.

The above-indicated object of the present invention may be achievedaccording to a principle of the invention, which provides acommunication apparatus through which voice communication can beperformed, comprising: a line interface portion which receives andtransmits data form and to a line and which includes a data accessarrangement device in which is incorporated a detection circuit thatdetects at least one of a line voltage and a line current; a voicereproducing device which reproduces a voice that is based on voicecommunication data transmitted from the line to the line interfaceportion; and a volume adjuster which adjusts reproduction volume withwhich the voice is to be reproduced by the voice reproducing device, onthe basis of a detected value of the detection circuit

In the communication apparatus constructed according to the presentinvention, the reproduction volume of the voice reproducing device isadjusted by utilizing the detection circuit which is incorporated in thedata access arrangement device. Accordingly, it is not necessary toprovide, in the apparatus, a detection circuit for adjusting thereproduction volume, separately from or independently of the lineinterface portion. Therefore, this arrangement reduces the cost ofmanufacture and the size of the apparatus.

As the data access arrangement device, there is known one in which isincorporated a detection circuit that detects at least one of a linevoltage and a line current for connecting the data access arrangement tothe line so as to comply with line standards.

When the line is closed and the communication apparatus is connected tothe line, i.e., the line-closing-and-connection is established, the linevoltage and the line current are unstable. If the volume adjuster isoperated in such an unstable period of the line voltage and the linecurrent, the reproduction volume of the voice reproducing device may beimproperly adjusted.

In the light of the above, the communication apparatus of the presentinvention may be arranged to further comprise: a judging portion whichjudges, upon closing of the line and connection of the communicationapparatus to the line, whether the line voltage and the line currentfall within a specified range, on the basis of the detected value of thedetection circuit; and an operation controller which operates the volumeadjuster where the judging portion judges that the line voltage and theline current fall within the specified range.

In the arrangement described above, the volume adjuster is operatedafter the unstable period of the line voltage and the line current uponestablishment of the line-closing-and-connection has been terminated andthe line voltage and the line current have fallen within the specifiedrange. Accordingly, the volume adjuster adjusts the reproduction volumeby using the value of the detection circuit detected with the linevoltage and the line current being stable after theline-closing-and-connection. Therefore, this arrangement is effective toprevent the reproduction volume from being improperly adjusted by hevolume adjuster.

Where the present communication apparatus comprises aline-voltage•current adjuster which adjusts, upon closing of the lineand connection of the communication apparatus to the line, the linevoltage and the line current so as to fall within the specified range,on the basis of the detected value of the detection circuit, thecommunication apparatus may be arranged to further comprise an operationcontroller which operates the volume adjuster upon termination of theadjustment of the line voltage and the line current by theline-voltage•current adjuster. According to this arrangement, the volumeadjuster is operated after the line voltage and the line current havefallen within the specified range, whereby the reproduction volume canbe prevented from being improperly adjusted as in the above-indicatedarrangement in which the communication apparatus comprises the judgingportion.

The line-voltage•current adjuster may be arranged to adjust the linevoltage and the line current so as to fall within the specified range byadjusting a resistance value of a line-side port of the data accessarrangement device.

In the communication apparatus according to the present invention, thevolume adjuster may be arranged to adjust, upon operation thereof, thereproduction volume on the basis of the detected value of the detectioncircuit such that the reproduction volume is increased or decreased, forsetting the reproduction volume at an optimum level. In thisarrangement, the reproduction volume of the volume reproduction deviceis adjusted to be increased or decreased, so that the reproductionvolume can be kept at the optimum level depending upon the line status.

If the reproduction volume is excessively large at the commencement ofthe reproduction of the voice, the user may be surprised at theexcessively large volume. In view of this, the volume adjuster may bearranged to adjust, on the basis of the detected value of the detectioncircuit, the reproduction volume of the voice reproducing device suchthat the reproduction volume is increased, so as to set the reproductionvolume at the optimum level.

Where the voice reproducing device is arranged such that thereproduction volume is selectively changed between at least two levelsconsisting of a large-volume level and a small-volume level and suchthat the reproduction volume is kept at the small-volume level until thevolume adjuster is operated, the volume adjuster may be arranged tojudge, upon operation thereof whether the reproduction volume needs tobe changed to the large-volume level, on the basis of the detected valueof the detection circuit, and change the reproduction volume to thelarge-volume level when it is judged that the reproduction volume needsto be changed to the large-volume level. This arrangement eliminates arisk of surprising the user upon reproduction of the voice due to anexcessively large reproduction volume.

The volume adjuster according to the arrangement described just abovemay be arranged to compare the detected value of the detection circuitwith a prescribed reference value and judge whether the reproductionvolume needs to be changed on the basis of a result of the comparison.This arrangements permits easy and speedy changing of the reproductionvolume.

The communication apparatus of the present invention may furthercomprise: a handset device utilized for performing voice communication;and a modem utilized for performing facsimile communication, so thatvoice communication and facsimile communication can be performed throughthe communication apparatus. Where the communication apparatus comprisesthe handset device and the modem, a primary-side•secondary-sideinsulation circuit may be provided on a path which connects the modemand the handset device to the data access arrangement device in such amanner that permits transmission and reception of data therebetween, forinsulating the modem and the handset device which are on a secondaryside, from the line which is on a primary side.

It may be considered that a separate line control portion (networkcontrol unit) for voice communication is provided on a path connectingthe data access arrangement device of the line interface portion to atelephone line and that a primary-side secondary-side insulation circuitis provided on a path connecting the data access arrangement to themodem while, at the same time, another primary-side•secndary sideinsulation circuit is provided on a path connecting the line controlportion to the handset device. Such an arrangement, however, requiresprovision of a plurality of insulation circuits in the apparatus,undesirably pushing up the cost of its manufacture.

In contrast, where the modem and the handset device are connected to thedata access arrangement in a way that permits transmission and receptionof data therebetween and the primary-side•secondary-side insulatingcircuit is provided on the path connecting the modem and the handset tothe data access arrangement, for insulating the modem and the handsetdevice which are on the secondary side, from the line side which is onthe primary side, only one insulation circuit is needed in theapparatus.

In the communication apparatus arranged to perform voice communicationand facsimile communication as described above, the data accessarrangement device is arranged to handle voice communication data andfacsimile communication data. Accordingly, a converting circuit isprovided for converting voice communication data transmitted from theline to the data access arrangement device into a signal that can beprocessable by the handset device for outputting the converted signal tothe handset device and for converting an output signal of the handsetdevice into voice communication data that can be processable by the dataaccess arrangement device.

The converting circuit may be arranged to obtain, via theprimary-side•secondary-side insulating circuit, the voice communicationdata transmitted from the line to the data access arrangement device andto output the voice communication data converted from the output signalof the handset device, to the data access arrangement device via theprimary-side•secondary-side insulation circuit.

According to the present invention, where the communication apparatus isarranged such that voice communication and facsimile communication canbe performed, the apparatus construction can be simplified and the costof manufacture of the apparatus can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features, advantages and technical andindustrial significance of the present invention will be betterunderstood by reading the following detailed description of a preferredembodiment of the invention, when considered in connection with theaccompanying drawings, in which:

FIG. 1 is a block diagram showing an electric configuration of afacsimile apparatus according to the present embodiment;

FIG. 2A is a block diagram showing a configuration of a communicationsection and FIG. 2B is a block diagram showing a configuration of avoice processing portion;

FIG. 3 is a block diagram showing a configuration of a line interfaceportion;

FIG. 4 is a flowchart showing communication processing executed by aCPU;

FIG. 5 is a flowchart showing line-closing-and-connection processingexecuted by the CPU; and

FIG. 6 is a graph showing relationship between (a) line voltage and linecurrent and (b) line standards.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

There will be described one embodiment of the present inventionreferring to the drawings. FIG. 1 is a block diagram showing anelectrical configuration of a facsimile apparatus 1 to which theprinciple of the present invention is applied and which is one kind of acommunication apparatus of the present invention. FIG. 2A is a blockdiagram showing a configuration of a communication section 21 and FIG.2B is a block diagram showing a configuration of a voice processingportion 45. FIG. 3 is a block diagram showing a configuration of a lineinterface portion 40.

The facsimile apparatus 1 of the present embodiment includes a CPU 11, aROM 13, a RAM 15, an EEPROM 17, an image memory 19, the communicationsection 21, a scanner 23, a coding section 25, a decoding section 27, aprinter 29, an operation panel 31, and a display 33, which are connectedto one another by a bus line.

The CPU 11 controls each of the sections and components 13-33 connectedby the bus line, and establishes, for instance, facsimile communication,voice communication, etc., by controlling the communication section 21.The ROM 13 stores various programs executed by the CPU 11 while the RAM15 is utilized as a working memory for temporarily storing various dataupon execution of various programs by the CPU 11. The EEPROM 17 isutilized as a memory for storing various setting information relating tothe facsimile apparatus 1.

The image memory 19 is a memory for storing read data produced by thescanner 23, received data which are received from an external facsimileapparatus, etc. Read data produced by the scanner 23 are stored in theimage memory 19. Facsimile data received by the communication section 21are stored in the image memory 19 after having been converted intodecoded data by the decoding section 27 and the stored data are clearedfrom the image memory 19 after having been printed by the printer 29.

The communication section 21 is utilized for facsimile communication andvoice communication, and includes the line interface portion 40, aprimary-side•secondary-side insulation portion 42, a modem 43, the voiceprocessing portion 45, a speakerphone device 47, and a handset device49. (Each component and device will be explained in greater detail.) Thescanner 23 optically reads a supplied draft or a manuscript by using animage sensor, for instance, and generates read data based on the outcomeby reading.

The coding section 25 codes read data produced by the scanner 23 andproduces facsimile data which are image data for facsimile transmission.The decoding section 27 decodes facsimile data transmitted from theexternal facsimile apparatus and received by the communication section21. The facsimile data are converted into data whose format can behandled by the printer 29.

The printer 29 prints, on a print sheet, an image which is based ondecoded data produced by the decoding section 27 or an image which isbased on read data produced by the scanner 23. The printer 29 is anink-jet printer, for instance. The operation panel 31 is provided withnumber keys from 0 to 9 and various operation keys. Upon operation ofthose keys by the user, information indicative of the operation isinputted to the CPU 11. The display 33 is constituted by a liquidcrystal display, for instance, and displays various information inaccordance with commands from the CPU 11.

There will be next explained the configuration of the communicationsection 21. The line interface portion 40 of the communication section21 is a circuit for receiving and transmitting data (such as voicecommunication signals, facsimile communication signals, etc.) from andto a line side (i.e., a side of an exchanger 3). The line interfaceportion 40 is constituted by including a semiconductor DAA (data accessarrangement) device 41. The present facsimile apparatus 1 is connectedto a telephone line LN that is connected to the exchanger 3 of publicswitched telephone network (PSTN), via the line interface portion 40.

The line interface portion 40 receives various signals transmitted fromthe public switched telephone network (PSTN), such as ring (call)signals from the exchanger 3 and voice communication signals and thefacsimile communication signals transmitted from an externalcommunication terminal equipment, and transmits, to the exchanger 3,communication signals necessary for facsimile communication and voicecommunication. Analog communication signals transmitted from thetelephone line LN to the line interface portion 40 are converted intodigital communication signals by a codec 65 of the line interfaceportion 40, and are outputted to the modem 43 via theprimary-side•secondary-side insulation portion 42.

The primary-side•secondary-side insulation portion 42 (hereinafter maybe referred to simply as “the insulation portion 42”) is provided in thelight of safety standards for insulating or separating the line side(primary side) and the modem side (secondary side) from each other. Theinsulation portion 42 includes condensers 42 a, 42 b which are disposedon a path that connects the semiconductor DAA device 41 of the lineinterface portion 40 and the modem 43 to each other in such a mannerthat permits transmission and reception of data therebetween. Thecondensers 42 a, 42 b establish DC insulation between (a) theprimary-side line interface portion 40 and (b) the secondary-side modem43 and devices and components which are disposed downstream of the modem43 (such as: the voice processing portion 45, the speakerphone device47, and the handset device 49 of the communication section 21; andvarious devices and components 11-19, 23-33 of the facsimile apparatus 1which are connected to the communication section 21 by the bus line).The insulation portion 42 further includes a transformer 42 c forsupplying, via the modem 43, power to the semiconductor DAA device 41 ofthe line interface portion 40.

The modem 43 includes a FAX-signal control portion 43 a which isoperated when facsimile communication is performed, a voice-signalcontrol portion 43 b which is operated when voice communication isperformed, and a serial interface 43 c which connects the FAX-signalcontrol portion 43 a and the voice-signal control portion 43 b to theline interface portion 40 in such a manner that permits transmission andreception of data therebetween.

The FAX-signal control portion 43 a is a signal-converting device forperforming facsimile communication with the external facsimileapparatus. The FAX-signal control portion 43 a produces a communicationsignal for facsimile transmission based on facsimile data produced bythe coding section 25, outputs the produced facsimile communicationsignal to the semiconductor DAA device 41 of the line interface portion40 via the insulating portion 42, and obtains, via the insulatingportion 42, a facsimile communication signal transmitted from the lineside to the semiconductor DAA device 41 of the line interface portion40, for extracting facsimile data therefrom. In addition to theconversion operation described above, the FAX-signal control portion 43a transmits and receives various procedure signals for transmissioncontrol.

The voice-signal control portion 43 b connects the voice processingportion 45 that is connected to the handset device 49 and thesemiconductor DAA device 41 of the line interface portion 40 to eachother in such a manner that permits transmission and reception of datatherebetween, when voice communication is performed. The voice-signalcontrol portion 43 b outputs, as a voice communication signal fortransmission, a digital voice signal inputted from the voice processingportion 45, to the semiconductor DAA device 41 of the line interfaceportion 40 via the insulation portion 42. Further, the voice-signalcontrol portion 43 b outputs a digital voice communication signalinputted from the line interface portion 40 via the insulating portion42, as a digital voice signal.

The voice processing portion 45 includes a codec 51: which converts adigital voice signal inputted from the voice-signal control portion 43 binto an analog voice signal that can be reproduced by the handset device49 or the speakerphone device 47 and outputs the analog voice signal tothe handset device 49 or the speakerphone device 47; and which convertsan analog voice signal inputted from the handset device 49 or thespeakerphone device 47 into a digital voice signal that are processableby the voice-signal control portion 43 b and the semiconductor DAAdevice 41 of the line interface portion 40 and outputs the digital voicesignal to the voice-signal control portion 43 b of the modem 43.

The sound processing portion 45 includes: an amplifier 53 whichamplifies an analog voice signal inputted from the handset device 49 orthe speakerphone device 47 and outputs the amplified analog voice signalto the codec 51; an amplifier 55 which amplifies an analog voice signalinputted from the codec 51; a selector 57 which selectively outputs ananalog voice signal inputted from either one of the handset device 49and the speakerphone device 47 to the voice-signal control portion 43 bof the modem 43 via the amplifier 53 and the codec 51; and a selector 59which outputs an analog voice signal outputted from the codec 51 andamplified by the amplifier 55, to either one of the handset device 49and the speakerphone device 47.

The amplifiers 53, 55 are arranged such that each gain (signalamplification factor) thereof can be changed in two steps consisting ofa “LOW” level and a “HIGH” level (LOW/HIGH) and performs gain adjustment(for adjusting the gain to the “LOW” level or the “HIGH” level) uponreception of commands from the CPU 11. The selectors 57, 59 arecontrolled by the CPU 11 so as to be connected to one of the handsetdevice 49 and the speakerphone device 47.

The handset device 49 used when voice communication is performed is aknown handset device including a transmitter 49 m constituted by amicrophone and a receiver 49 r constituted by a speaker. Thespeakerphone device 47 permits hand-free communication and includes aspeaker 47 r and a microphone 47 m. At the receiver 49 r and the speaker47 r, a voice which is based on a voice communication signal transmittedfrom the line side to the line interface portion 40 is reproduced, onthe basis of an output signal from the selector 59.

Next, there will be explained in detail the configuration of the lineinterface portion 40. The line interface portion 40 according to thepresent embodiment includes, in addition to the semiconductor DAA device41, a diode bridge 60 for rectifying polarity of a DC loop current ofthe line network in one direction, loop cut condensers 62 a, 62 b, 62 c,62 d, an adjustment circuit 64 for adjusting a resistance value of aline-side port of the semiconductor DAA device 41, etc. To the lineinterface portion 40, a two-wire telephone line LN is connected viaterminals TL1, TL2.

The semiconductor DAA device 41 of the line interface portion 40includes: a serial interface 61 that is connected to the serialinterface 43 c of the modem 43 via the insulation portion 42; a ringdetection circuit 63; the codec 65; a reception amplifier 67; atransmission amplifier 69, a voltage detection circuit 71; and a hybridnetwork 73.

The ring detection circuit 63 is connected to the telephone line LN viathe terminals TL1, TL2. The ring detection circuit 63 detects a ringsignal upon arrival thereof from the telephone line LN and outputs, tothe serial interface 61, a ring detection signal which changes at thesame cycle as the ring signal. A ring detection signal inputted to theserial interface 61 is outputted to the modem 43 via a transmission pathin which is interposed the condenser 42 b of the insulation portion 42.When a ring detection signal is inputted to the modem 43, the modem 43notifies the CPU 11 of the input of the ring detection signal.

The codec 65 includes an analog-to-digital conversion circuit and adigital-to-analog conversion circuit. After the line has been closed andconnected to the facsimile apparatus 1 (i.e.,line-closing-and-connection has been established), the codec 65 convertsan analog communication signal (a voice communication signal or afacsimile communication signal) received from the line side (the publicswitched telephone network) via the telephone line LN, into a digitalcommunication signal, and outputs the digital communication signal tothe modem 43 via the serial interface 61. Further, the codec 65 convertsa digital communication signal (a voice communication signal or afacsimile communication signal) inputted from the modem side, into ananalog communication signal, and outputs the analog communication signalto the telephone line LN side.

The codec 65 is connected to the telephone line LN via the receptionamplifier 67 and to the hybrid network via the transmission amplifier69. Further, the codec 65 is connected to an output end of the voltagedetection circuit 71 so as to convert a detection signal of the voltagedetection circuit 71 into a digital signal and output the digital signalto the modem side. When a detection signal of the voltage detectioncircuit 71 is inputted to the modem 43, the modem 43 outputs theinputted detection signal to the CPU 11.

The reception amplifier 67 is a differential amplifier and outputs ananalog communication signal inputted from the terminals TL1, TL2 thatare connected to the telephone line LN, to the codec 65 in adifferential input method. The transmission amplifier 69 is arranged toamplify an analog communication signal outputted from the codec 65 andinput the amplified analog communication signal to the hybrid network73.

The voltage detection circuit 71 detects a line voltage which is appliedto the semiconductor DAA device 41 after having been rectified by thediode bridge 60 and is connected to a path which connects the diodebridge 60 and the hybrid network 73 to each other. A detection signal ofthe voltage detection circuit 71 (indicative of a voltage value) isoutputted to the codec 65, and then to the CPU 11 from the codec 65 viathe modem 43.

The hybrid network 73 transmits, to the telephone line LN, acommunication signal for transmission (a facsimile communication signalor a voice communication signal) outputted from the codec 65 via thetransmission amplifier 69. In order to form a closed loop which complieswith the line standards, the hybrid network 73 adjusts a resistancevalue of a line-side end thereof by operation of the adjustment circuit64 which is disposed on a path connecting the hybrid network 73 and thetelephone line LN, thereby adjusting the line voltage and a linecurrent. The line-port end of the hybrid network 73 is the line-sideport of the semiconductor DAA device 41.

The adjustment circuit 64 includes: a transistor Tr whose collector isconnected to the diode bridge 60; a condenser C and a resistance R1which are disposed on a path connecting the collector of the transistorTr and the hybrid network 73; and a resistance R2 which is disposed on apath connecting an emitter of the transistor Tr and the ground.

The hybrid network 73 is connected to a base and the emitter of thetransistor Tr and forms the closed loop upon turning on the transistorTr, thereby closing the line. The hybrid network 73 adjusts a basepotential to be applied to the transistor Tr, and thereby adjusts theresistance value of the line-side end of the hybrid network 73, so as topermit the line voltage and the line current to comply with the linestandards. The hybrid network 73 is also connected to the serialinterface 61 and controlled by the CPU 11 via the serial interface 61and the modem 43.

The serial interface 61 described above unifies a ring detection signalfrom the ring detection circuit 63, a digital communication signaloutputted from the codec 65, etc., into serial signals, and output theserial signals to a transmission path in which is interposed thecondenser 42 a. Further, the serial interface 61 separates each ofserial signals inputted from the modem 43 via the transmission path inwhich is interposed the condenser 42 b and outputs the separated serialsignals to each portion or device of the semiconductor DAA device 41.

There will be next explained communication processing executed by theCPU of the facsimile apparatus 1. FIG. 4 is a flow chart showing thecommunication processing executed by the CPU 11 and FIG. 5 is a flowchart showing line-closing-and-connection processing executed by the CPU11.

When the communication processing is executed, Step S110 (hereinafter“Step” is omitted if appropriate) is initially implemented in which theCPU 11 waits until a line-closing-and-connection command is inputtedwhen the handset device 49 is placed in an off-hook state by the user orwhen an off-hook key provided on the operation panel 31 is pushed by theuser. Where it is judged at S110 that the line-closing-and-connectioncommand has been inputted (“YES” at S110), a line-closing-and-connectionprocessing task is started at S120, and the control flow then goes toS140.

In the line-closing-and-connection processing shown in the flow chart ofFIG. 5, the CPU 11 obtains a value detected by the voltage detectioncircuit 71 which is incorporated in the semiconductor DAA device 41(S121), and judges whether the line voltage indicated by the detectedvalue falls within a normal or appropriate range (S123). This step(S123) is for detecting abnormality of the voltage which results fromimproper connection of the telephone line LN to the line interfaceportion 40, for instance.

If it is judged at S123 that the line voltage is not normal (“NO” atS123), the CPU 11 delivers, at S139, line-closing-and-connection failurenotification which indicates that the line-closing-and-connection hasnot been established, to a communication processing task, terminatingthe line-closing-and-connection processing.

On the other hand, if the line voltage is judged to be normal at S123(“YES” at S123), the CPU 11 controls the semiconductor DAA device 41 toperform line-closing-and-connection operation (S125). More specificallydescribed, the CPU 11 controls the hybrid network 73 to apply the basepotential to the transistor Tr of the adjustment circuit 64, therebyturning on the transistor Tr to form the closed loop with the exchanger3.

Thereafter, the CPU 11 obtains a value detected by the voltage detectioncircuit 71 (S127). Further, the CPU 11 calculates a line current on thebasis of the detected value of the voltage detection circuit 71 andrecognizes the line voltage and the line current (S129).

After the processing at S129 is terminated, the CPU 11 judges whetherthe line voltage is higher than a predetermined limit voltage (S131).Where it is judged at S131 that the line voltage is higher than thelimit voltage (“YES” at S131), the CPU 11 controls the semiconductor DAAdevice 41 to perform line-opening-and-disconnection operation (S132).Thereafter, the CPU 11 delivers the line-closing-and-connection failurenotification to the communication processing task (S139), terminatingthe line-closing-and-connection processing.

On the other hand, where the line voltage is judged to be not higherthan the limit voltage at S131 (“NO” at S131), the CPU 11 judges, on thebasis of the processing result at S129, whether the line voltage and theline current fall within a specified range (S133). If the line voltageand the line current are judged to fall within the specified range atS133 (“YES” at S133), the CPU 11 delivers, to the communicationprocessing task, line-closing-and-connection completion notificationwhich indicates that the line-closing-and-connection is completed(S135).

FIG. 6 is a graph showing relationship between (a) line voltage and linecurrent and (b) line standards. Where the line voltage and the linecurrent fall within the specified range indicated in the graph of FIG.6, the CPU 11 makes an affirmative judgment (“YES”) at S133, andterminates the line-closing-and-connection processing after theprocessing at S135 has been implemented.

Where the CPU judges that the line voltage and the line current do notfall within the specified range at S133 (“NO” at S133), the CPU 11controls the hybrid network 73 to adjust the base potential of thetransistor Tr of the adjustment circuit 64 such that the line voltageand the line current fall within the specified range (S137), and thecontrol flow then goes to S127. For instance, where the line current isunder the specified range, the line current is adjusted so as to beincreased by increasing the base potential of the transistor Tr, i.e.,by increasing the amount of current flowing through the transistor Tr.Where the line current is over the specified range, on the other hand,the line current is adjusted so as to be decreased by decreasing thebase potential of the transistor Tr, i.e., by decreasing the amount ofcurrent flowing through the transistor Tr.

The adjustment of the base potential at S137 is repeated until the linevoltage and the line current are judged to fall within the specifiedrange at S133. Where the line voltage and the line current fall withinthe specified range, the CPU 11 makes an affirmative judgment (“YES”) atS133, and delivers the line-closing-and-connection completionnotification to the communication processing task (S135), terminatingthe line-closing-and-connection processing.

In the meantime, the CPU 11 judges, at S140 of the communicationprocessing, whether the line-closing-and-connection completionnotification is delivered from the line-closing-and-connectionprocessing task. If the CPU 11 judges that theline-closing-and-connection completion notification has not beeninputted (“NO” at S140), the CPU 11 judges whether theline-closing-and-connection failure notification is delivered (S145). Ifthe CPU 11 judges that the line-closing-and-connection failurenotification has not been delivered (“NO” at S145), the CPU 11 waitsuntil the line-closing-and-connection completion notification or theline-closing-and-connection failure notification is delivered from theline-closing-and-connection processing task. If the CPU 11 judges thatthe line-closing-and-connection failure notification is delivered (“YES”at S145), the communication processing is terminated.

Where the CPU 11 judges that the line-closing-and-connection completionnotification is delivered (“YES” at S140), the CPU 11 sets each gain ofthe amplifiers 53, 55 of the voice processing portion 45 at the “LOW”level (S15 o), and connects the amplifiers 53, 55 to one of the handsetdevice 49 and the speakerphone device 47 (S155). By implementing thisstep (S155), the handset device 49 or the speakerphone device 47 isconnected to the voice-signal control portion 43 b of the modem 43 andaccordingly to the semiconductor DAA device 41 in such a manner whichenables transmission and reception of data (voice signals) therebetweenwhile a reproduction volume with which a voice is to be reproduced bythe handset device 49 or the speakerphone device 47 is made at asmall-volume level.

In a case where the line-closing-and-connection command is judged to beinputted at S110 as a result of placing the handset device 49 in theoff-hook state, the CPU 11 controls, at S155, the selectors 57, 59 toconnect the amplifiers 53, 55 to the handset device 49. In a case wherethe line-closing-and-connection command is judged to be inputted at S110as a result of pushing the off-hook key provided on the operation panel31, the CPU 11 controls, at S155, the selectors 57, 59 to connect theamplifiers 53, 55 to the speakerphone device 47.

After the voice-control portion 45 and one of the handset device 49 andthe speakerphone device 47 have been connected to each other, the CPU 11checks the line current (S160). At this step S160, the CPU 11 obtains avalue detected by the voltage detection circuit 71 and indicative of theline voltage, and obtains the line current by calculation on the basisof the detected value.

Subsequently, the CPU 11 judges whether the obtained line current ishigher than a threshold or reference value (S170). Where the linecurrent is judged to be higher than the threshold value at S170 (“YES”at S170), the CPU 11 controls the amplifiers 53, 55 such that each gainof the amplifiers 53, 55 is set at the “LOW” level (S173). On the otherhand, where the line current is judged to be not higher than thethreshold value at S170 (““NO” at S170), the CPU 11 controls theamplifiers 53, 55 such that each gain of the same 53, 55 is set at the“HIGH” level (S177).

After the processing at S172 or S177, the CPU 11 judges whether aline-opening-and-disconnection command is inputted (S180). Where it isjudged by the CPU 11 that the line-opening-and-disconnection command isnot inputted (“NO” at S180), the CPU 11 again implements S160 throughS173 or S177 to again adjust each gain of the amplifiers 53, 55 on thebasis of the line current obtained again in S160. The CPU 11 judges atS180 that the line-opening-and-disconnection command is inputted whenthe handset device 49 is placed in an on-hook state or when an on-hookkey provided on the operation panel 31 is pushed. Where it is judged atS180 that the line-opening-and-disconnection command is inputted (“YES”at S180), the CPU 11 controls the semiconductor DAA device 41 to openthe line and disconnect the facsimile apparatus 1 from the line (S190),terminating the communication processing.

In the present facsimile apparatus 1, the line interface portion 40 fortransmitting and receiving data (communication signals) to and from theline side includes the semiconductor DAA device 41 in which isincorporated the voltage detection circuit 71 capable of detecting theline voltage. In the thus constructed facsimile apparatus 1, when thehandset device 49 is placed in the off-hook state and theline-closing-and-connection command is inputted, the CPU 11 controls thehybrid network 73 to close the line and connect the facsimile apparatus1 to the line, i.e., to establish the line-closing-and-connection (atS125). Upon establishment of the line-closing-and-connection, the basepotential to be applied to the transistor Tr of the adjustment circuit64 is changed on the basis of the detected value of the voltagedetection circuit 71 for adjusting the resistance value of the line-sideend of the hybrid network 73, whereby the line voltage and the linecurrent fall within the specified range.

When the adjustment of the resistance value described above is completedand the line voltage and the line current fall within the specifiedrange, the CPU 11 judges that the line voltage and the line current fallwithin the specified range and then carries out consequentvolume-adjustment processing (S160 through S180). Namely, each gain ofthe amplifiers 53, 55 of the voice processing portion 45 is adjusted onthe basis of the line current obtained from the detected value of thevoltage detection circuit 71, and the volume of the voice to bereproduced by the receiver 49 r of the handset device 49 or the speaker47 r of the speakerphone device 47 (the reproduction volume) is set at alevel suitable to the line current. Described more specifically, theline current obtained from the detected value of the voltage detectioncircuit 71 is compared with the threshold value (the reference value),and each gain of the amplifiers 53, 55 of the voice processing portion45 is changed to the “LOW” level or the “HIGH” level on the basis of theresult of comparison, so that the reproduction volume is changed betweenthe two levels, i.e., the large-volume level and the small-volume level.

When the volume-adjustment processing described above is initiallyimplemented, it is judged that each gain of the amplifiers 53, 55 needsto be changed if the line current is not higher than the threshold value(“NO” at S170). In this instance, by changing each gain of theamplifiers 53, 55 from the “LOW” level to the “HIGH” level, thereproduction volume of the receiver 49 r or the speaker 47 r is changedso as to be increased, that is, the reproduction volume is changed fromthe small-volume level to the large-volume level. Where the line currentis higher than the threshold value, on the other hand, each gain of theamplifiers 53, 55 is kept at the “LOW” level and therefore thereproduction volume is kept at the small-volume level (S173) until thevolume-adjustment processing (S160 through S180) is carried out afterthe voice outputting has been ready, i.e., after the voice-reproducingpreparation has been completed (S155).

In the present embodiment wherein the reproduction volume of thereceiver 49 r and the speaker 47 r is adjusted by utilizing the voltagedetection circuit 71 which is incorporated or integrated in thesemiconductor DAA device 41, it is not necessary to provide, separatelyfrom the line interface portion 40, a detection circuit for thereproduction-volume adjustment, resulting in reduction in the cost ofmanufacture and the size of the facsimile apparatus 1.

In the facsimile apparatus 1 of the illustrated embodiment, the linecurrent is estimated on the basis of the detected line voltage and eachgain of the amplifiers 53, 55 is set so as to correspond to theestimated line current after an unstable period of the line voltage andthe line current upon establishment of the line-closing-and-connectionhas been terminated and the line voltage and the line current havefallen within the specified range. This arrangement prevents improperadjustment of the reproduction volume during the unstable period of theline voltage and the line current.

In the facsimile apparatus 1, each gain of the amplifiers 53, 55 is setat the “LOW” level for minimizing the reproduction volume at the time ofcommencement of the voice outputting after the connection of theselectors 57, 59 to one of the handset device 49 or the speaker device47 has been completed, and the reproduction volume is kept at thesmall-volume level until the volume-adjustment processing (S160 throughS180) is initiated. Thereafter, when it is judged that the line currentis not higher than the threshold value, eah gain of the amplifiers 53,55 is adjusted such that the reproduction volume is increased. Thus,this arrangement is effective to avoid dissatisfaction of the user whicharises from an excessively large reproduction volume at the time ofcommencement of the voice outputting.

In the illustrated embodiment, each gain of the amplifiers 53, 55 isarranged to be changed between the two levels so as to enable thereproduction volume to be changed between the two volume levels, and thereproduction volume is arranged to be changed on the basis of the resultof comparison between the line current obtained from the detected valueof the voltage detection circuit 71 and the threshold value. Thisarrangement realizes speedy and proper adjustment of the reproductionvolume with the simple apparatus structure, permitting manufacture ofthe satisfactory apparatus at a relatively low cost.

In the facsimile apparatus 1 according to the illustrated embodiment,the primary-side•secondary-side insulation portion 42 is provided on thetransmission path connecting the semiconductor DAA device 41 and themodem 43 to each other in a way which permits transmission and receptionof data therebetween. Further, the handset device 49 is connected to themodem 43 via the voice processing portion 45. Accordingly, it is notrequired to dispose a plurality of insulation portions on thetransmission path of voice communication signals and the transmissionpath of facsimile communication signals, respectively. In other words,the primary side and the secondary side can be connected while beinginsulated by the single insulation portion 42. Hence, the facsimileapparatus 1 of the illustrated embodiment can be manufactured at arelatively low cost.

The volume adjuster of the present invention is realized by theprocessing at S160-S180 executed by the CPU 11 while the judging portionis realized by the processing at S133 executed by the CPU 11. Theoperation controller is realized by the operation of the CPU 11 toexecute the processing at S160 and the following steps upon judgment ofthe CPU at S140 that the line-closing-and-connection has been completed.The line-voltage•current adjuster is realized by theline-closing-and-connection processing executed by the CPU 11, theoperation of the hybrid network 73 based on theline-closing-and-connection processing, and the operation of theadjustment circuit 64. In the illustrated embodiment, the voicereproducing device is constituted by the voice processing portion 45 andthe handset device 49 or the speakerphone device 47. The convertingcircuit corresponds to the codec 51 of the voice processing portion 45.

It is to be understood that the present invention may be embodied withvarious changes and modifications, which may occur to those skilled inthe art, without departing from the spirit and scope of the invention.

In the illustrated embodiment, each gain of the amplifiers 53, 55 isadjusted by using the semiconductor DAA device 41 in which isincorporated the voltage detection circuit 71 which is capable ofdetecting the line voltage. Each gain of the amplifiers 53, 55 may beadjusted by using a semiconductor DAA device in which is incorporated acurrent detection circuit which is capable of detecting the linecurrent. By considering the circuit configuration, the line current canbe accurately estimated from the detected voltage, and the line voltagecan be accurately estimated from the detected current, so that theadjustment of each gain of the amplifiers 53, 55 on the basis of theline current can be properly performed where either one of the voltagedetection circuit and the current detection circuit is incorporated inthe semiconductor DAA device.

While each gain of the amplifiers 53, 55 is changed between the twolevels in the illustrated embodiment, each gain of the amplifiers 53, 55may be adjusted among a plurality of levels (more than two levels). Inthis instance, the reproduction volume may be adjusted to be increasedby adjusting the gain in steps from a smaller level to a higher level.

1. A communication apparatus through which voice communication can beperformed, comprising: a line interface portion which receives andtransmits data form and to a line and which includes a data accessarrangement device in which is incorporated a detection circuit thatdetects at least one of a line voltage and a line current; a voicereproducing device which reproduces a voice that is based on voicecommunication data transmitted from the line to the line interfaceportion; and a volume adjuster which adjusts reproduction volume withwhich the voice is to be reproduced by the voice reproducing device, onthe basis of a detected value of the detection circuit.
 2. Thecommunication apparatus according to claim 1, wherein the data accessarrangement device is a semiconductor data access arrangement device. 3.The communication apparatus according to claim 1, further comprising: ajudging portion which judges, upon closing of the line and connection ofthe communication apparatus to the line, whether the line voltage andthe line current fall within a specified range, on the basis of thedetected value of the detection circuit; and an operation controllerwhich operates the volume adjuster where the judging portion judges thatthe line voltage and the line current fall within the specified range.4. The communication apparatus according to claim 1, further comprising:a line-voltage•current adjuster which adjusts, upon closing of the lineand connection of the communication apparatus to the line, the linevoltage and the line current so as to fall within the specified range,on the basis of the detected value of the detection circuit; and anoperation controller which operates the volume adjuster upon terminationof the adjustment of the line voltage and line current by theline-voltage•current adjuster.
 5. The communication apparatus accordingto claim 4, wherein the line-voltage•current adjuster adjusts the linevoltage and the line current so as to fall within the specified range byadjusting a resistance value of a line-side port of the data accessarrangement device.
 6. The communication apparatus according to claim 1,wherein the volume adjuster adjusts, upon operation thereof thereproduction volume on the basis of the detected value of the detectioncircuit such that the reproduction volume is increased or decreased. 7.The communication apparatus according to claim 1, wherein the voicereproducing device is arranged such that the reproduction volume isselectively changed between at least two levels consisting of alarge-volume level and a small-volume level and such that thereproduction volume is kept at the small-volume level until the volumeadjuster is operated, and wherein the volume adjuster judges, uponoperation thereof, whether the reproduction volume needs to be changedto the large-volume level, on the basis of the detected value of thedetection circuit, and changes the reproduction volume to thelarge-volume level when it is judged that the reproduction volume needsto be changed to the large-volume level.
 8. The communication apparatusaccording to claim 7, wherein the volume adjuster compares the detectedvalue of the detection circuit with a prescribed reference value andjudges whether the reproduction volume needs to be changed, on the basisof a result of the comparison.
 9. The communication apparatus accordingto claim 1, further comprising: a handset device utilized for performingvoice communication; and a modem utilized for performing facsimilecommunication, so that voice communication and facsimile communicationcan be performed through the communication apparatus, wherein aprimary-side•secondary-side insulation circuit is provided on a pathwhich connects the modem and the handset device to the data accessarrangement device in such a manner that permits transmission andreception of data therebetween, for insulating the modem and the handsetdevice which are on a secondary side, from the line which is on aprimary side.
 10. The communication apparatus according to claim 9,further comprising a converting circuit which converts voicecommunication data transmitted from the line to the data accessarrangement device into a signal that can be processable by the handsetdevice for outputting the converted signal to the handset device andwhich converts an output signal of the handset device into voicecommunication data that can be processable by the data accessarrangement device, wherein the converting circuit is arranged toobtain, via the primary-side•secondary-side insulation circuit, thevoice communication data transmitted from the line to the data accessarrangement and to output the voice communication data converted fromthe output signal of the handset device to the data access arrangementdevice via the primary-side•secondary-side insulation circuit.